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(11) | EP 0 424 111 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Video signal processing apparatus |
| (57) Video signal processing apparatus is provided for use with a video camera (13) having
a line scanning line period during which useful video information is provided and
a flyback period during which an optical black signal level. Replacement black signal
information that is a function of the optical black signal level is inserted (17)
into a portion of the flyback period. When the camera (13) is of the type having a
complementary colour matrix filter which produces odd and even raster scan lines of
image pick-up signals with different modulation components, contour correction is
provided. Modulation components in a scan line of image pick-up signals caused by
the patterns of filter elements included in the matrix are removed (56), thereby producing
an averaged scan line of image signals from which is extracted a signal component
that is uncorrelated from one line to the next. Prior to such extraction, that portion
of an averaged scan line of image signals which exceeds a predetermined level that
is less than the lowest average level of a scan line of image signals which would
saturate video processing circuitry (67, 69, 70) is clipped (61, 63, 65). The extracted,
uncorrelated signal component is combined (73) with an averaged scan line of image
signals to produce a contour-emphasized luminance signal. |